Unlike most other inborn errors of metabolism, which require advanced and expensive diagnostic techniques and complex drug and dietary management (often not feasible in developing countries), the renal tubular acidoses may be detected and treated both easily and cheaply. Diagnostic confusion is possible as this series demonstrates due to the protean clinical manifestations. Three recent cases from Port Moresby General Hospital are described and appropriate investigations and treatment discussed.
Acidosis, Renal Tubular - diagnosis ; Acidosis, Renal Tubular - metabolism ; Child, Preschool ; Female ; Humans, Infant

Type IV renal tubular acidosis (RTA) is due to renal tubular bicarbonate wasting associated with mineralocorticoid deficiency. In its five subtypes, IV-4 is due to pseudohypoaldosteronism (PHA) evidenced by increased plasma renin and aldosterone. PHA is believed to result from distal tubular unresponsiveness to circulating aldosterone and has normal renal and adrenal fuction. Hypoaldosteronism can easily be suspected when the patient shows typical electrolyte imbalance (hyponatremia coupled with hyperkalemia) and the diagnosis of PHA is confirmed by elevated serum aldosterone level. But some patients of PHA show negligible electrolyte imbalance, thus metabolic acidosis is a sole abnormal finding in routine laboratory examination. We experienced a case of IV-4 RTA in a 2-month-old male infant who presented with normal anion gap-metabolic acidosis as a sole abnormal finding in routine laboratory examination. RTA was suspected and the test of urine pH during systemic acidosis and fractional excretion of bicarbonate (FEHCO3-) during the condition of normal plasma bicarbonate concentration revealed the disease to be type IV RTA. With elevated plasma renin activity and aldosterone level, the diagnosis of type IV-4 RTA (pseudohypoaldosteronism) was made. Type IV RTA is the most common form of RTA, therefore it is recommended that young infants with suspected RTA should be checked for serum aldosterone level first.
Acidosis ; Acidosis, Renal Tubular* ; Aldosterone ; Diagnosis ; Humans ; Hydrogen-Ion Concentration ; Hypoaldosteronism ; Infant ; Male ; Plasma ; Pseudohypoaldosteronism ; Renin

Acidosis, Renal Tubular ; diagnosis ; Female ; Humans ; Infant ; Mitochondrial Diseases ; diagnosis ; Seizures ; diagnosis

Primary renal lymphoma is one of the malignant lymphomas that initially presents in the extra lymphonode, which is rarely seen in children. This study reported two cases of primary renal lymphoma in children who were definitively diagnosed by renal biopsy. Renal tubular acidosis was the initial manifestation in both cases. They were referred to the hospital with chief complaints of polydipsia, polyuria, debilitation, vomiting and anemia. Imaging and laboratory examinations showed bilateral renomegaly, hypocalcemia, hypophosphatemia, and metabolic acidosis. One of the patients discontinued therapy. The other received chemotherapy including prednisone, vincristine, cytarabine and L-asparaginase, combined with intrathecal injections of methotrexate, dexamethasone and Ara-C and supporting treatment. Twenty-three days after treatment, polydipsia and polyuria were relieved, and acidosis, kaliopenia and anemia were improved in the patient. There were no abnormal findings in the renal B-ultrasound re-examination. It was concluded that when a patient is suspected of renal lymphoma, diagnostic puncture and renal biopsy should be performed early. Early combined therapeutics including chemotherapy, radiation therapy, surgery and supporting treatments may result in a favorable prognosis in patients with this disease.
Acidosis, Renal Tubular ; diagnosis ; etiology ; Child ; Humans ; Kidney Neoplasms ; complications ; Lymphoma ; complications ; Male

Distal renal tubular acidosis (RTA) caused by autoimmune nephritis occurs in up to 25% of patients with Sjögren's syndrome. However, patients with hypokalemic paralysis are sometimes overlooked, because most symptoms of autoimmune nephritis in Sjögren's syndrome are mild. We present a case of hypokalemic paralysis in a 54-year-old female who also had dry eyes and mouth, and Raynaud's phenomenon. Further evaluation, including autoantibody tests, revealed distal RTA with Sjögren's syndrome as the cause of hypokalemia. Distal RTA diagnosis was made based on normal anion gap hyperchloremic metabolic acidosis, alkaline urine with positive urine anion gap, high transtubular potassium concentration gradient (TTKG), positive anti-La antibody, and symptoms of sicca complex. The patient's symptoms resolved following treatment with intravenous and oral potassium, immunosuppressants, and steroids. This case illustrates that distal RTA and Sjögren's syndrome should be considered in cases of hypokalemic paralysis.
Acid-Base Equilibrium ; Acidosis ; Acidosis, Renal Tubular* ; Diagnosis ; Female ; Humans ; Hypokalemia ; Immunosuppressive Agents ; Middle Aged ; Mouth ; Nephritis ; Paralysis* ; Potassium ; Steroids

Acidosis, Renal Tubular ; complications ; diagnosis ; Child ; Diagnostic Errors ; Female ; Humans ; Medullary Sponge Kidney ; complications ; diagnosis ; Rickets ; diagnosis

Systemic lupus erythematosus (SLE) is a multisystem disease with marked variability in its manifestation. Tubulointerstitial involvement is well recognized in SLE. But usually the tubular dysfunction is latent and usually presents after diagnosis of SLE. We report a 20 years old female whose initial symptom of SLE was distal renal tubular acidosis (RTA). She presented with severe muscle weakness at emergency room with laboratory fingding consistent with distal RTA. After several months she developed fever, arthritis, serologic fingding which was compatible to diagnose SLE. We report a case whose initial symptom of SLE had been distal RTA.
Acidosis, Renal Tubular* ; Arthritis ; Diagnosis ; Emergency Service, Hospital ; Female ; Fever ; Humans ; Lupus Erythematosus, Systemic* ; Muscle Weakness ; Young Adult

Primary Sjögren's syndrome (pSS) is characterized by lymphocytic infiltration of the exocrine glands resulting in decreased saliva and tear production. It uncommonly involves the kidneys in various forms, including tubulointerstitial nephritis, renal tubular acidosis, Fanconi syndrome, and rarely glomerulonephritis. Its clinical symptoms include muscle weakness, periodic paralysis, and bone pain due to metabolic acidosis and electrolyte imbalance. Herein, we describe the cases of two women with pSS whose presenting symptoms involve the kidneys. They had hypokalemia and normal anion gap metabolic acidosis due to distal renal tubular acidosis and positive anti-SS-A and anti-SS-B autoantibodies. Since one of them experienced femoral fracture due to osteomalacia secondary to renal tubular acidosis, an earlier diagnosis of pSS is important in preventing serious complications.
Acid-Base Equilibrium ; Acidosis ; Acidosis, Renal Tubular* ; Autoantibodies ; Diagnosis ; Exocrine Glands ; Fanconi Syndrome ; Female ; Femoral Fractures ; Glomerulonephritis ; Humans ; Hypokalemia ; Kidney ; Muscle Weakness ; Nephritis, Interstitial ; Osteomalacia ; Paralysis ; Saliva ; Tears

Autoimmune hemolytic anemia (AIHA) is a relatively common cause of anemia in children and adults with systemic lupus erythematosus (SLE). Although AIHA responds to steroids, in case of refractory or steroid-dependent AIHA, immunosuppressants and intravenous immunoglobulin have been used as second line agents. Rituximab, an anti-CD20 monoclonal antibody, is emerging in the treatment of SLE refractory to conventional therapy. Herein, we report a case of delayed and sustained remission of refractory hemolytic anemia in a child with SLE, post rituximab treatment. A 12-year-old female child with dizziness was referred to our department and was diagnosed with SLE combined with hemolytic anemia and renal tubular acidosis. Since frequent relapse of hemolytic anemia had occurred during the steroid tapering course, even though she had been treated with additional immunosuppressants (azathioprine, mycophenolate mofetil), the patient received 2 doses of rituximab 500 mg at 2 weeks interval at 18 months post diagnosis. After 15 months of rituximab administration, her anemia and renal tubular acidosis were fully recovered, enough to stop all medications. She remained well without recurrence for up to 3 years and 4 months after rituximab treatment.
Acidosis, Renal Tubular ; Adult ; Anemia ; Anemia, Hemolytic* ; Anemia, Hemolytic, Autoimmune ; Child* ; Diagnosis ; Dizziness ; Female ; Humans ; Immunoglobulins ; Immunosuppressive Agents ; Lupus Erythematosus, Systemic* ; Recurrence ; Steroids ; Rituximab

BACKGROUND: Diagnosis of RTA (renal tubular acidosis) is not easy due to its nonspecific and various manifestations. To find out the clues to diagnosis, we investigated initial manifestations, laboratory features and clinical course of RTA patients. METHODS: Thirty-seven patients with RTA type I or II, whose follow-up period was over 6 months were included in the study. We reviewed their medical records retrospectively. RESULTS: Male to female ratio was 5:32 and the average age at the time of diagnosis was 38.7 (15~60). Twenty-five patients had RTA type I, nine had type II, and three had both. The average follow-up period was 6.4 years. Initial manifestations were asthenia (54%), nausea (46%), urinary stone (24%), paresthesia (24%), lower extremity weakness (22%), and paralysis (11%). Underlying diseases at the time of diagnosis include Sjogren's syndrome (14%), SLE (8%), drug-induced nephropathy (11%), diabetic nephropathy (5.4%), Sjogren's syndrome combined with SLE (2.7%), and medullary sponge kidney (2.7%). Laboratory tests revealed acidosis with hypokalemia (59%), acidosis without hypokalemia (14%), and hypokalemia without acidosis (24%). The level of total CO2 was 22 mmol/L or lower in 27 patients. The Na:Cl ratio on the average was 1:1.26 and for 33 patients below 1:1.35. Renal function deteriorated in 8 patients and 7 of them had underlying diseases. Urinary stone developed in 2 patients with RTA type I. CONCLUSION: When patients with nonspecific symptoms show decreased levels of serum total CO2, potassium, or Na:Cl ratio, RTA should always be considered.
Acidosis ; Acidosis, Renal Tubular* ; Asthenia ; Diabetic Nephropathies ; Diagnosis ; Female ; Follow-Up Studies ; Humans ; Hypokalemia ; Lower Extremity ; Male ; Medical Records ; Medullary Sponge Kidney ; Nausea ; Paralysis ; Paresthesia ; Potassium ; Retrospective Studies ; Sjogren's Syndrome ; Urinary Calculi